Update codecov requirement from = 0.2.3 to = 0.2.15

Updates the requirements on [codecov](https://github.com/codecov/codecov-ruby) to permit the latest version.
- [Release notes](https://github.com/codecov/codecov-ruby/releases)
- [Changelog](https://github.com/codecov/codecov-ruby/blob/master/CHANGELOG.md)
- [Commits](codecov/codecov-ruby@v0.2.3...v0.2.15)

Signed-off-by: dependabot[bot] <support@github.com>

lazylead.gemspec

@@ -77,7 +77,7 @@ tasks instead of solving technical problems."
   s.add_runtime_dependency "tzinfo-data", "1.2019.3"
   s.add_runtime_dependency "vcs4sql", "0.1.1"
   s.add_runtime_dependency "viewpoint", "1.1.0"
-  s.add_development_dependency "codecov", "0.2.3"
+  s.add_development_dependency "codecov", "0.2.15"
   s.add_development_dependency "guard", "2.15.0"
   s.add_development_dependency "guard-minitest", "2.4.6"
   s.add_development_dependency "minitest", "5.11.3"